The invention relates to a monitoring method and a stationary unit for a motor-driven door. In this connection the term door will be understood as any means with which a building or a site can be closed, and it includes, for example, sliding doors, rolling doors, sectional doors or swinging doors.
In particular, the invention relates to a method implemented by a battery-powered monitoring device mounted on the door leaf or door curtain, which device is intended for wireless data exchange via a bidirectional radio link with a stationary unit, and to a method for fail-safe and power-saving operation of the monitoring device.
From the prior art (DE 10302812 A1) there is known a monitoring device and a monitoring method for a motor-driven building closure, especially a door. This prior art door is equipped with a motor-drive group for driving a movable door wing and with a controlling device for control and monitoring of the movement of the wing. The controlling device comprises a first fixed electrotechnical unit and a second movable electrotechnical unit, which is mounted to ride on the wing and which can communicate with the fixed unit. A riding transmitter-receiver is provided on the wing next to the riding unit and a fixed transmitter-receiver is provided next to the fixed unit, whereby the two transmitter-receivers permit the two units to communicate wirelessly with one another. In this prior art door, the transmitter-receiver is capable of pulsed operation and the riding transmitter-receiver as well as the riding unit can be switched from a power-saving waiting state to an operating state. The riding transmitter-receiver is automatically controllable, in the sense that it repeatedly switches from a waiting state to the operating state and back to the waiting state, if during the operating state it has not detected an activating, uncoded signal from an optional fixed unit in the form of sufficiently high field strength.
This prior art device has the disadvantage that a plurality of doors cannot be operated simultaneously with this door controller. The transmitter-receiver of a first door switches automatically to an operating state. If it receives a signal with sufficiently high field strength, it remains active. In this way, it may happen that the transmitter-receivers of a plurality of doors mounted in parallel with one another remain active concurrently and thus consume power unnecessarily.
Further prior art (U.S. Pat. No. 5,412,297 A) is a closing-edge unit, which monitors a door for proper and obstruction-free closing. According to this prior art there is provided a vibration sensor, which senses the door movement and activates control electronics equipped with a microprocessor and a signal transmitter sufficiently long that it detects the door movement. After being wakened, the transmitter outputs a continuous first “heartbeat” signal. As soon as the closing-edge unit has detected an obstruction, it sends another heartbeat signal, which is different from the first heartbeat signal. If the door controller receives this second heartbeat signal or does not receive either of the two heartbeat signals, either the door movement is stopped or the door movement is reversed, until the door is completely open. The “heartbeat” signal is interrupted, for example, in the event of a defect of the closing-edge unit.
This prior art method has the disadvantage that, for flawless functioning, the vibration sensor must be exposed during the entire door movement to vibrations that are sufficiently strong that it can reliably detect the door movement. In the case of linear movement of a smoothly running door, this conceals the danger that the vibration sensor may misinterpret this condition as a stationary door, causing the first heartbeat signal to be turned off and in turn a malfunction. Certainly this problem could be avoided by using a vibration sensor with very high sensitivity. However, such a sensitive vibration sensor would have the disadvantage that the closing-edge unit would be wakened and fully activated whenever a vibration was sensed, thus causing normal power consumption. If the vibration sensor senses a signal, for example because strong wind is “shaking” the door, the entire electronics are wakened, and so the power consumption of this prior art device is relatively high. Furthermore, this device has the disadvantage that it cannot reliably distinguish whether the door is executing a closing movement or an opening movement. Under some circumstances, this causes the entire electronics to be awake, to transmit its “heartbeat” signal and thus to consume power even during the opening movement, in which monitoring is not necessary for many doors.
The cited disadvantages also apply to the prior art closing-edge unit according to U.S. Pat. No. 7,123,144 B2, since the closing-edge unit described therein also functions only in a manner dependent on detection of a door movement by a motion detector.
Also known from the prior art (US 2006/0028157 A1) is a device that sends out a “check signal” as soon as a pneumatic sensor is tripped by the fact that the door has encountered an obstacle. Stopping and reversing of the door are initiated on the basis of this “check signal”, which is received by a door controller.
This prior art device has the disadvantage that it is decidedly unsafe, since the door controller cannot reliably determine whether it is capable at all of receiving the “check signal”.